The Milun Fault sliped in 1951 and 2018 and caused serious seismic hazards in the Hualien City. The current scientific evidence indicates the reoccurrence interval of the Milun Fault may be as short as 67 years and this means the probability of next slip is 53% within 50 years from now.
The last event in 2018 was a medium magnitude earthquake but still made serious damage because it goes throught the Hualien City. All stations within 5 km from the fault recorded pulse-like velocities with a PGV of near 150 cm/s and periods of 2 sec to 3 sec. The observed accelerations were therefore higher than the current design spectrum at long period.
We propose three topics in this project from the aspect of seismic hazard prevention.
The topic one is to install two downhole arrays in the boreholes next to the Milun Fault. We will install two downhole accelerometers in the two arrays for monitoring strong motions and site response of the near surface. The topic two is to study detail near surface velocity structure by microtremor arrays and velocity logging. We will analyze existing strong motion recordings and those will be recorded by the expected network to further understand ground motion characteristics under the topic three, to give comments for seismic hazard prevention and seismic design code in the area.
Hopefully we may promote research on both seismology and engineering seismology in Taiwan by the collaboration between earthquake physics and strong motions.
